Is OpenCL possible within Blender either via cycles or internal?
Blender Internal
BI never had any kind of GPU rendering support, and as development on BI has stopped, probably never will.
Cycles
Cycles only supports cuda at the moment, due to issues with amd/ati drivers. (also see the wiki)
However, there are some experimental tests using the &quot;leaked beta version of what might be AMD's next official drivers&quot; which you may want to try.